Piston expanding apparatus



D. RUBIN PISTON EXPANDING APPARATUS Sept. 26, 1939.

3 Sheets-Sheet 1 Filed Dec. 1, 1937 r I I 1 I! r IIIIIIIIIIIIIII 1 |1|llllll WM I 'L mwvv 6 Vldz Gttornega,

Se t. 26,1939. RUBIN -2',174,217'

PISTON EXPA-NDING APPARATUS Filed Dec. 1, 1957 3 Sheets-Sheet 2 Il HWIH Sept. 26, 1939. DRUBlN 2,174,217

PI STON EXPANDING APPARATUS w i I luv itutente field Ed, '11

UNITED STATES ,nau

PVATE QFFICE 2,174,211- PISTON ExPANoiNG APPARATUS Application December 1, 1937, Serial No. llllfitid 7 Claims.

This invention relates generally to devices for decreasing the clearance of pistons in the cylinders oi internal combustion motors and more particularly to machines for expanding the pistons oi. such motors.

This application is a continuation-in-part of my copending application Serial Number 118,964, filed January 4, 1937.

v Internal combustion engines after a certain lib amount of use, lose compression and power owing to the fact that the piston rings, cylinder wall and piston skirt become worn down. The cylinder maybe rebored and new rings and piston installed, but it is cheaper to replace the M1 worn rings with new ones and use the old piston.

The old piston because of its relatively reduced diameter, oscillates about the piston pin and between the cylinder walls giving rise to what is lrncwn as piston slap. It is well known to 2p insert a resilient expansive device within the piston skirt to enlarge the same, but this is unsatisfactory for many reasons, including the facts that insufficient enlargement is obtained and the characteristics of the piston are altered. as Inasmuch as the new piston rings provide increased compression, I have found that if the piston skirt is expanded transversely of the piston pin, piston slap" is removed and oil consumption is considerably reduced. I have also found so that if instead of being expanded, the piston skirt is ovalized (a reduction of the skirt diameter, longitudinally of the piston pin and a corresponding increase in piston skirt diameter transversely of. the pin) an improved motor performance is obtained. Where the piston skirt is slotted a combination of expanding and ovalizing is very satisfactory.

While it has been proposed to expand piston shirts by hammering or peeping them to an no expanded shape, this has been unsatisfactory in that insufficient expansion is produced and the peening causes the metal to crystalize and become brittle.

The present invention contemplates the physical expansion of the piston skirt while same is in a heated and annealed condition. After the stretching operation is completed, the piston is retcmpered so that its original metallic condition is restored but the new shape is retained. The

metal heating and treatment varies with the metallic composition of the piston.

In my co-pending application, Serial Number 167,473, filed October 5, 1937, now Patent Number 2,133,403, I have disclosed and claimed a method oi expanding pistons, such method involving certain steps of heating, stretching, and cooling. The invention disclosed and claimed in the present application relates more especially to apparatus for expanding pistons, e. g., in accordance with the method disclosed in my co-pending d application, Serial Number l67,l73, now Patent Number 2,133,403. lit will be understood, however, that apparatus embodylng my present invention is not restricted in use to the practice of the particular method referred to.

The main object oi the present invention is the provision of structure whereby a simple, efficient and inexpensive device accurately expands pistons of various types.

Another object is the provision of a device of w the class described which may be conveniently adjusted to handle pistons of various types.

Another object is the provision c1. 2. device of the class described which contains structure for supporting and retaining the piston in proper W position while the same is being stretched or expanded.

. Another object is the provision of a measuring device in conjunction with the expanding machine tor accurately determining the expanded 25 piston size.

A further object of the invention is the provision of improved replaceable piston expanding abutments capable of accommodating the internal structure of various types of pistons.

A still iurther object is to provide means ior adjusting the alignment of the piston-engaging abutments. Other objects will become apparent from a reading of the following description, the appended claims, and the accompanying drawings, in which:

Figure l is a fragmentary plan view of one preferred embodiment oi the invention;

Figure 2 is a fragmentary elevational view of A0 Figure l: l

Figure 3 is an enlarged fragmentary elevational view of the front of the machine shown in Figure 1;

Figure l is an elevational front view of an alter- 45 nate type of piston expanding peg;

Figure 5 is a sectional view of Figure 4 as seen from the plane 5-% thereon;

Figure 6 is a bottom view of the moving piston peg shown on Figure 3 as seen from the plane 50 3-43 thereon;

Figure 7 is a top plan view of a further preferred embodiment of the invention;

Figure 8 is a view in side elevation of. the embod ment shown in Figure. 7; 55

Figure 9 is a longitudinal vertical sectional view taken on the line 9-9 of Figure '7;

Figure 10 is a vertical cross sectional view taken on the line III-I of Figure 7; and

Figure 11 is a detail perspective view of a piston-engaging abutment.

Form shown in.- Figu'res 1 to 6 inclusive Referring first to the embodiment shpwn in Figures 1 to 6 inclusive, there is showna casing or frame I6 supporting the operating parts and having a top I I which serves conveniently as a stationary work table. The front and back walls I2 and I 3 respectively and the side walls I4 and I5 may be sufliciently extended downwardly to enclose the heating and tempering ovens (not shown) for treating the pistons before and after stretching.

The stretching or expanding assembly, generally indicated by numeral I6, is composed essentially of a stationary arm I! and a moving arm or carrier I8 upon which are detachably mounted a stationary piston expansion abutment or peg I9 and a movable piston expansion abutment or peg 26, respectively. Stationary arm I! is of rigid construction and is securely mounted, by means of two bolts 2|, to the bottom surface of top I I and projects horizontally forward through the left end of a horizontally disposed oblong orifice 22 in front wall I2. Moving arm I6 is the load arm of a long lever or carrier 24 mounted simlhrly to arm H, but is pivotally connected to top II by means of bolt 23 which threadedly engages the underside of said top similarly to bolts 2|. The rear end of lever 24 has a nut 25 pivotally attached thereto, and the nut in turn is threadedly mounted on a transversely mounted screw 26. Screw 26 is trunnioned in side walls I4 and I5 and penetrates the latter to have a large hand wheel 21 affixed to the terminal thereof. Sufficient clearance 28 is provided, longitudinally with respect to lever 24, to allow for the arcuate travel of the rear end of said lever, so that the manual actuation of hand wheel 21 will result in the arm I6 and peg 26 slowly and powerfully approaching or receding from arm I1 and peg 26, depending upon the direction of rotation of the hand wheel.

It is, of course, apparent that other means of actuation of arm I6 may be employed, such as hydraulic, or compound lever means, but the means described above have been found efllcient and inexpensive.

The abutments or pegs I 6 and 26 may be identical in construction and interchangeable; hence a description of peg I9 will sumce for both. The working face 55 is plane, vertical, and transversely disposed with relation to the principal direction of motion of peg 26. Face 55 is provided with a horizontal rabbet 56 at the lower edge thereof, and a horizontal groove 51. The purpose of these depressions is to permit horizontally disposed reinforcing ribs on the internal surfaces of the piston skirt to fit therein so that the expanding pressure may be exerted against the relatively smooth portions of the cylindrical inner walls of the piston skirt. The placement of these depressions may be varied to suit the individual requirements of difl'erent types of pistons but the configuration shown in Figure 3 has been found satisfactory for nearly all ordi-,

nary pistons. The inner face 56 is provided with a deep rabbet 66, preferably curved at-59' so that the strain is evenly distributed and the likelihood of breakage is reduced. An integral shank 66 threaded adjacent the end thereof, penetrates a vertically disposed orifice in arm I! and a nut 6| when tightened down securely clamps the peg I9 in place. Peg 2l1 is.similarly attached to the arm I6.

In Figures 4 and 5 there is illustrated an alternate type of peg. This peg 62 has a working head 63 which is adapted to swivel about the pivot 64 and the working face 65 has a cylindrically shaped surface. The peg 62 is substituted in place of peg 20 when the piston skirt is of a type having vertically disposed reinforcing ribs,,or when the piston skirt is provided with a diagonally disposed slot. The face 65 is adapted to fit between the said vertical ribs or to distribute pressure over a sufliciently large area around the diagonal slot so that the skirt is not fractured. The curvature of face 65 may be a1- tered to coincide with the configuration of different pistons, where advisable. Peg 62 is provided with a shank 66' which is inserted in the opening in the forward end of arm I8 and is secured with the'nut 6i. Pivot head 64" prevents the head 63 from slipping off while shoulder 64" provides a smooth bearing surface 1n place of the upper-face of arm I6, so thatthe head 63 may readily rotate.

A clamping device 29 is used to hold the piston to ,the stationary peg I9 before and after the piston is acted on by peg20 so that the piston will not become displaced and in order that accurate measurements may be made before, during, and after the stretching or expanding operation. This device 29 comprises a support arm 30, and a clamping face plate 3|. Since the piston is comparatively light and the pegs I9 and 20 maintain it in place while the piston is being expanded, the clamping device need not exert very great pressure. The face plate 3| is supported by an integral rod 32 perpendicularly projecting from the rear thereof to penetrate the forward end of support arm 36, and terminate in the operating knob 33. A spiral expansive spring 34 serves to force the face plate 3| against the piston skirt and clamp it against peg IS. The support arm 30 is adjustably'clamped at the rear end thereof to arm I1 by means of the thumbscrew 35. The forward portion of arm 30 is offset so that a sufllcient clearance is provided for the insertion of the piston skirt and the operation of the face plate 3|.

A measuring device 36 is provided for readily and accurately determining the amount of expansion given the piston skirt. Such a device comprises preferably a rim-set dial micrometer 31 whose feeler 38 is adapted to contact the outer surface of the piston skirt on a line with the centers of pegs I9 and 26. The micrometer 31 is adjustably mounted by virtue of the following assembly. Bolt 39 which freely penetrates top II, and pivotally carries the rear end of arm 4| may be tightened in position by thumb-nut 40. Arm 4| penetrates orifice 22. A spacer 42 has two integral screw ends of reduced diameter, the upper one of which penetrates an orifice in the forward end of arm 4| and is adJustably clamped by a thumb nut 43; and the lower one which penetrates an orifice in the rear end of arm 44 and is adjustably clamped by a thumbnut 45. Theforward end of arm 44 is adjustably and pivotally connected to the micrometer by the integral threaded shank 46 depending from said micrometer which penetrates said arm and is clamped by thumb-nut 41. Wherever desirable,

the spac r 42, may be made adjustable, or other suitable mechanism may be utilized for varying the effective height of the micrometer.

An adjustable work table 48 is vertically regulable for supporting pistons of different heights and is pivotally mounted in a horizontal plane so that it may be swung into and out of position as needed. The horizontal face 49 issupported by an integral vertical post 50 which is in turn clamped in the bifurcated end of an arm 5|, the rear end of which is pivotally mounted on an inverted L shaped bracket 52 aflixed to the front wall I2. Actuation of thumb-screw 53 allows adjustment in a horizontal plane and actuation of thumb-nut 54 allows adjustment in a. vertical plane.

Operation of the inclusive Knob 83 is pulled out and the heated piston is placed up under pegs I9 and- 20, with the piston pin parallel to the arm I1, and the skirt outside of the pegs, whereupon knob 33 is released. The table 48 is swung underneath the piston head and adjusted to support the piston in the position indicated by the dashingle-dot lines on Figure 3. The measuring devic is adjusted so that the feeler 38 contacts the outer wall of the piston skirt and is properly aligned as set forth above. The micrometer is adjusted to zero reading. Hand wheel 21 is manipulated and the desired expansion or stretch is given to the piston skirt as the peg 20 moves away from peg I9. This procedure is then reversed and the piston is removed.

It may now be noted that the connecting rod and piston assembly may be treated without removing the connecting rod from the piston. The connecting rod is placed between the arms I1 and 'I 8 while the piston pin and connecting rod knuckle find noobstruction because of the rabbets 59.

The machine is shown set up on Figures 1, 2, and 3 for operating on pistons with the piston head down. In this arrangement it is easy for the operator to see into the piston and carefully adjust same with relation to the pegs. Where it is desired, however, the pegs I9 and 20 may be inverted and the clamping device swung up to take the position indicated by the dash-doubledot lines on Figure 3. The measuring device may also be raised by reversing the positions of arm 44 and spacer 42. Inthis position the piston is treated with the head up, and is placed as indicated by the dash-triple-dot lines on Figure 3.

Form shown in Figures 7 to 11 inclusive Figures '7 to 11 inclusive show a further preferred embodiment of the invention which is somewhat similar in general structural arrangement and mode of operation to the form shown in Figures 1 to 6 inclusive, but which also includes other advantageous features.

In the embodiment shown in Figures '7 to 11, which may be carried upon a support S, there is provided a frame generally designated I00 which conveniently may be fabricated of side track or guide members I0l--I02 spaced apart at their left hand ends, as viewed in Figures '7, 8, and 9, by means of a block I03 to which the side members are secured by bolts I04. At their right hand ends the guide members IOI--I02 are connected together in spaced relation by means of a cross piece I05 and bolts I06.

- A carrier or cross head generally designated I0! is mounted for sliding movements on the guide members I0 I-I02. In the form shown, the cross head comprises a block I08 and upper and lower form shown in Figures 1 to 6 plates I08 secured, to the block by means of bolts H0. The plates I 09 extend laterally beyond the sides of the block to provide flanges III adapted to ride on the upper and lower surfaces of the guide members IOI-I02. Preferablyythe block I08 is'of a thickness, measured vertically, somewhat less than the height of the guide members, the plates I00 being spaced slightly from the top and bottom faces of the block by means of replaceable shims II2. This arrangement provides for adjusting the position of the block I08 with respect to the guide members so as to properly position or align the block relative to the guide members. i

Any suitable power or manually operated means may be provided for moving the carrier or cross head along the guide members. In the form shown, there is provided a screw I I3 having an eye I I4 positioned in a recess II5i-n the cross head block I08, and a bolt IIG secured .to the cross head and passing through the eye. -The outer end of the screw extends through the internally threaded sleeve II'I journalled in the cross piece I05 of the frame and being provided with a crank II8.

In accordance with the invention, piston-engaging abutmentsin the present instance comprising pegs II9I20--are carried by the blocks I03 and I08, being respectively secured thereto by studs as in the first form of the invention. The arrangement is such that a piston P shown fragme'ntarily in Figure 9 is positioned over the pegs H9 and I20 with the lower surface of the piston skirt resting upon the frame and, block I08. The pegs I I9 and I20 are arranged to contact respectively with opposite surface portions of the inside of the piston skirt, so that, upon relative separating movement of the pegs, effected by rotation of the screw and movement to the right of the cross head, the pegs will press outwardly against the skirt at diametrically opposite sides thereof so as to stretch or expand the skirt. Preferably, the mgs extend well into the piston and have contact with the inner surface of the skirt over a. substantial area considered longitudinally of the piston axis. Many present-day pistons are provided with internal stiffening projections, such as beads or ribs, and the piston P is disclosed as having such a rib designated p.

In order to provide for the extended contact area between the pegs and skirt of a piston provided with such a projection, the pegs are formed with recesses or depressions H9 and I20 respectively adapted to accommodate the projection 29, at the same time permitting the remainder of the operative face of each peg to lie snugly against the inner surface of the piston skirt.

In accordance with a further feature of the invention, the pegs themselves are so constructed as to provide for adjustment of the piston-engaging surfaces thereof in a manner to permit a very accurate alignment of the pegs with respect to the piston surface, and with respect to each other. A preferred construction making such adjustment possible comprises pegs H9 and I20 formed with splits at I I9 and I20 respectively, thus providing fork-like or bifurcated members. Thus the, peg H9, by virtue of the split, is formed with a rela tively heavy part II9 and a relatively light part H9. A screw 9 having threaded engagement with the heavy part II!) engages the lighter part II9, so that operation of the screw springs the lighter part relative to the heavier part, thus effecting a change in the alignment of the lighter or piston-engaging part with respect to the piston tween the cross head block I08 and cross head plates I09, a primary adjustment of the cross head, and consequently of the peg I20, may be efiected.

After such primary or relatively coarse adjustment has been made, a final and finer adjustment of the alignment of the piston-engaging surfaces of the pegs may be made by operation of either one or both of the screws H9 and I20 These adjustments are particularly convenient and important when the apparatus is used for expanding pistons of various designs. I have found that the inner surfaces of the skirts of different types and makes of pistons taper axially ofthe pistons to varying degrees. The adjustments provided in accordance with the present invention make it possible to expand various kinds of pistons without providing special abutments for each particular design of piston.

The embodiment shown in Figures 7 to 11 inclusive,as well as that disclosed in Figures 1 to 6, may advantageously be provided with an indicator gauge or the like for measuring or indicating the amount of stretching or expansion of the piston being worked upon. As shown, a dial gauge I2l having a feeler I2I is mounted upon a screw I 22 having threaded engagement with a bracket I23 secured to the frame by means of a screw I24. A lock nut I25 on the screw I24 serves to clamp the bracket I23 in adjusted position, and a lock nut I26 on the screw I22 serves to clamp the screw and hence the gauge in adjusted position with respect to the bracket. The gauge thus is so mounted as to be adjustable relative to the frame. In use, the gauge is adjusted or moved to such position that the feeler I2 I engages the outer surface of a piston skirt prior to expanding thereof. Then the screw I I3 is rotated to move the cross head to the right so as to effect relative separating movement of the abutments and stretching of the piston until the gauge indicates that the predetermined desired amount of stretching has taken place.

Operation of the form shown in Figures 7 to 11 inclusive To recapitulate the mode ofuse and operation of the embodiment shown in Figures '7 to 11, it will be assumed that the parts are in the position shown in Figures 7 and 8. The first step is to operate the screw I I3 so as to move the cross head and abutment peg I20 toward the left until the distance between the outer faces of the pegs III) and I20 is considerably less than the inside diameter of the piston skirt. The piston is then placed over the pegs, and, if it is found that the outer faces of the peg portions H9 and I20 do not align with the associated inner piston skirt portions, the necessary adjustments of one or both of the pegs are effected in the manner already described. The gauge is then set so that the feeler I2 I- engages the outer surface of the piston, and the screw is rotated in the opposite direction until the gauge shows that the proper amount of stretchinghas taken place. Thereafter the screw is again rotated to move the cross head to the left so that the piston may be removed from the apparatus.

The apparatus shown herein embody the invention in preferred and commercially successful forms, but it is to be understood that changes may be made without departing from the invention as defined in the claims.

I claim:

1. In a piston skirt expanding apparatus, the combination of a frame; a first abutment in fixed relation to said frame and having a surface adapted to engage a first portion of the inside surface of a piston skirt; a carrier; a second abutment mounted on said carrier; means mounting said carrier on said frame with the carriermounted abutment substantially parallel to the piston-engaging surface of said first abutment; the portions of said frame and carrier adjacent the bases of the abutments being spaced apart, said frame and carrier outwardly of the abutments having surfaces in a common plane for contact by an internally-engaged article; and means for moving said carrier to effect relative separating movement of said abutments, the last mentioned means also functioning to retain the carrier in its different positions.

2. In a piston skirt expanding apparatus, a combination as set forth in claim 1 and in which the carrier comprises an arm pivoted to the frame.

3. In a piston skirt expanding apparatus, a combination as defined in claim 1 and in which the frame includes a guide and the carrier comprises a cross head slidable on the guide, and in overlapping engagement with opposite sides thereof.

4 In a piston skirt expanding apparatus having abutments mounted on a frame and adapted to engage spaced portions of the inside surface of a piston skirt, at least one of said abutments comprising a split member having a heavy portion and a relatively light portion, the latter portion being outermost and being directly engageable with a piston skirt, and means having bearing cooperation with said heavy portions for effecting relative movements between said heavy and light portions to deflect said light portion out of parallelism with said heavy portion.

5. In a piston skirt expanding apparatus, an abutment comprising a split fork-like member and means for effecting relative movements between the portions thereof on opposite sides of the split.

6. In a piston skirt expanding apparatus, an abutment comprising a split fork-like member having a relatively heavy portion on one side of the split therein and a relatively light portion on the other side of the split, and an adjusting screw having threaded engagement with said relatively heavy portion and bearing upon the relatively .light portion.

7. In apparatus for expanding a piston skirt having a projection on the inner surface thereof such as an annular stiffening rib or bead, the combination of a frame to support the piston, a pair of abutments rising from the frame in spaced relation to each other having oppositely disposed faces adapted respectively to engage the inner surface of the piston skirt on opposite sides thereof, said faces being elongated axially of the piston to engage the skirt over an area extending over a substantial part of the axial length thereof, at least one of said abutments being formed with a depression to accommodate said projection; and means for effecting relative separating movement of the abutments while the piston is supported on the frame to effect engagement with and disengagement from said depression.

DAVID RUBIN. 

